"You need to make a commitment to the American people so they come in to get tested," Rep. Katie Porter, D-Calif., said.
After five minutes of questions from Porter, Redfield committed to free coronavirus testing.
Tune into ABC at 1 p.m. ET and ABC News Live at 4 p.m. ET every weekday for special coverage of the novel coronavirus with the full ABC News team, including the latest news, context and analysis.
"I think you're an excellent questioner, so my answer is yes," he said. Trump signed a bill mandating free coronavirus testing several days later.
The moment, viewed online more than 27 million times, highlighted one of Congress's important oversight tools: the ability to question key public officials under oath, and on camera.
In the weeks since that tense exchange, the importance of congressional oversight has grown given the scale of the outbreak in the country, and the government's $2.7 trillion -- and counting -- spending on the response.
But lawmakers, aides and experts say their efforts to monitor the fast-moving outbreak and spending have been complicated by social distancing and other mitigation efforts, and are off to a slow start.
"It was already going to be difficult. We have an administration that has resisted congressional oversight at every step," Noah Bookbinder, the executive director of Citizens for Responsibility and Ethics in Washington, told ABC News.
"You add to that the fact that everything now has to be done remotely, and you can't have hearings in person, and that Congress's rules tend to not be very flexible," Bookbinder said.
Social distancing has complicated oversight
As chairman of the House Intelligence Committee, Rep. Adam Schiff, D-Calif., is used to spending several hours a day in secure committee rooms in the basement of the Capitol.
Now, with the committee conducting oversight with a "particular focus" on the coronavirus and the intelligence community -- what agencies learned, when they learned it and what they communicated about the virus -- the panel's work has been "hampered" by some of the necessary physical precautions needed to prevent the spread of the virus.
"There are real constraints when we can't be physically present, and other constraints when we can't get administration witnesses to come and testify on the Hill," Schiff told ABC News.
His staff has staggered their presence in the office suite -- which was temporarily closed after a former staffer tested positive for the coronavirus. Democratic members met in person for the first time this month last week, when the House voted on a new relief package.
"We had our first [bipartisan] video briefing this week," he said, adding that the system has security concerns. "We're going to try to do those every week, but those will have to be all open-source materials, so it puts real constraints on what we can do."
Other panels have made similar adjustments, with staff working from home and members fanned out across the country.
The House Oversight Committee has held conference calls with agency officials and lawmakers, to follow up on investigations related to the administration's response to the coronavirus.
Porter, who also sits on the panel, said the calls have been useful, but leave much less time for questioning of any administration officials.
"It's more like allowing them to tell us what they want to tell us," she said.
And unlike hearings, the calls aren't publicized and visible to the public.
"The American public doesn't know that we're getting those answers," she said.
New oversight measures aren't fully up and running
The new oversight mechanisms created in the $2.3 trillion CARES Act signed into law on March 27 are still getting set up, weeks into the efforts to stabilize the economy and handle the growing outbreak.
The Congressional Oversight Commission, a five-person panel overseeing Treasury and Federal Reserve stimulus efforts whose members are appointed by Democratic and Republican leaders, still lacks a chair to lead the group, even as it nears deadlines to begin producing reports to Congress.
Brian Miller, President Trump's nominee to serve as the special inspector general to supervise the pandemic recovery work at the Treasury Department, will testify before the Senate Banking Committee next week, roughly a month after his nomination. He will still need to be confirmed by the full Senate before he begins his work.
The Pandemic Response Accountability Committee (PRAC), another oversight entity established in the CARES Act that is made up of inspectors general from several government agencies, launched its website this week, roughly one month after its formation.
A group of inspectors general named Robert Westbrooks, a veteran investigator, to lead the group, after Trump removed Glenn Fine, the acting inspector general for the Defense Department initially tapped to lead PRAC, from his Pentagon post.
House Speaker Nancy Pelosi on Wednesday appointed Democrats to the new House select committee set up to supervise spending across the entire stimulus package, after naming Rep. Jim Clyburn, D-S.C., the Democratic whip, as chairman earlier this month.
Clyburn said he hopes that the full select committee will gather in Washington next week.
Republicans have been critical of the select panel, and voted against forming it. A spokesman for House Minority Leader Kevin McCarthy on Wednesday called the panel "impeachment 2.0," and the California Republican said on Thursday that he hasn't decided if his conference will participate in the effort.
For their part, Republicans on the House Oversight Committee on Thursday pushed Democrats to join their investigation of the World Health Organization and China's messaging around the initial outbreak of the coronavirus.
Trump administration continues to rebuff oversight
The Trump White House has resisted and rebuffed congressional oversight efforts since 2017, and has maintained that posture through the coronavirus outbreak -- compounding the difficulties for lawmakers.
Trump's nomination of Miller, a White House lawyer, angered Democrats who called for an apolitical appointee for the traditionally nonpartisan role.
And in his signing statement for the CARES Act, Trump also said he wouldn't allow that watchdog to share information with Congress without presidential supervision.
"There is zero reason for Trump to cooperate with the House right now," said Kurt Bardella, a former aide to House Oversight Chair Darrell Issa, R-Calif., who investigated the Obama administration. "His approach has been, ‘No, what are you going to do about it?'"
"The best case scenario is that Joe Biden becomes president, and that everything that happened in the federal government will become fertile ground for investigation by Democrats," said Bardella, now a Democrat and Trump critic.
House and Senate on different tracks
It's not clear when the House will have in-person hearings with administration officials under oath again.
House Democratic leaders, citing guidance from the Office of the Attending Physician, have decided against returning to Washington next week for business, and will wait to return until the next relief package is ready for a vote.
With an even more prolonged recess looking likely, the House has set up a bipartisan task force to determine how committees can best continue their business remotely.
Porter, speaking to ABC News from her home in California, said the chamber has "let six weeks go by in which we have not been doing that required study and getting ready" to conduct oversight hearings remotely.
A House Democratic aide told ABC News that leadership has been working on remote working and voting for several weeks, and is now working with Republicans on a bipartisan agreement on how to move forward with any changes with House rules.
Pelosi told reporters on Thursday that even with the House out of session, "small groups can come back," and that 60 panel meetings have been conducted "virtually or otherwise."
Across the Capitol, Majority Leader Mitch McConnell is planning to bring the Senate back next week, to begin resuming regular business and in-person work on the next relief package.
Some committees will resume hearings -- the Senate Intelligence Committee, for example, will hold a nomination hearing for Rep. John Ratcliffe, Trump's pick for director of national intelligence who has been criticized by Democrats.
And on Tuesday the Senate Banking Committee will hold a confirmation hearing for Miller, Trump's pick for special inspector general for pandemic recovery.
As for other committees, some Republican chairmen are anxious to hold oversight hearings, and concerned that some Democrats could use the platforms to embarrass Trump ahead of the 2020 election, according to two senior GOP aides. Leader are also concerned about calling in key administration officials during the pandemic, they said.